#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>

int Fac(int n)
{
	if (n <= 2)
		return 1;
	else
		return Fac(n - 1) + Fac(n - 2);
}

int main()
{
	int n = 0;
	while (scanf("%d", &n) != EOF)
	{
	int ret = Fac(n);
	printf("%d", ret);
	}
	return 0;
}